1. Field of the Invention
The invention relates to a cutting device, and more particularly, to a cutting device having both an auto-retractable blade and a spare blade box contained in a housing thereof.
2. Description of the Prior Art
Cutting device is a commonly used hand tool for cutting, e.g., wood, paper, leather, plastic panel, cord, and cardboard. It often has a housing made up of two covers detachably coupling together. The housing acts as both a handle and a container for a blade slidably received therein. An actuator is provided in an aperture defined in the handle for moving the blade.
In order to avoid hurting persons after cutting, some utility knives having auto retractable blade are provided. A blade of the cutting device is able to retract back into the housing when a user releases the actuator after cutting. However, dangers still exist when a user, who is abstracted or not agile enough to release the actuator, waves the cutting device to himself or other with his finger pressing on, the actuator and the blade extending after leaves a workpiece.
Cutting devices with a retractable blade in which the blade automatically retracts into the handle before a clumsy user can bring it toward himself or toward anyone else after a cutting edge of the blade leaves a workpiece are disclosed in U.S. Pat. No. 7,765,701 and U.S. Patent Application Publication No. 2009/0277016. Both cutting devices have a blade seat having a long tail extending backward and a hook formed on an also backward extending pole driven by a thumb actuator. In work, a user is able to move the actuator forward, and the hook will drive the long tail, thus the blade seat, forward, too. When the blade cuts the workpiece, the blade seat rotates and the long tail leaves the hook. As the blade leaves the workpiece, the blade seat is driven back by a spring. When the user releases the actuator, the pole is driven back by another spring and engages with the long tail again for next time use.
It is a trend for current utility knives that they all need to have an integral spare blade box defined in the housing thereof. A cutting device lack of integral spare blade box brings much inconvenience. However, all prior automatically retractable utility knives do not have such a spare blade box. The long tail and the backward extending pole occupy much of a rear portion of the housing, which usually belongs to, the spare blade box. Since the rotation of the blade in cutting is a very tiny one, a journey of travel of the backward extending pole to disengage with the long tail of the blade seat in cutting must be enlarged by a leverage mechanism. In another words, if there were not the long tail and the backward extending pole, a distance between the actuator and the blade seat before and after the cutting is too small for the actuator to credibly engage with the blade seat.